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[Page update] Junction box#Errors when editing

Post by Inactive user -1697532064-
I propose a small update to the Sixteen paths max bullet point in this section of the JB wiki
from
current JB wiki wrote:Sixteen paths max - No more than 16 controllable entry/exit paths can pass through a single junction node within a junction box. A save error occurs if a junction node has more than 16 connections. This also counts the adjacent connections not displayed in the routing box list that do not cross any of the internal segments like A to G, D to J, etc.
to
new JB wiki wrote:Sixteen paths max - No more than 16 allowed indirect (multi-node) entry/exit paths can pass through a single junction node within a junction box. A save error occurs if a junction node has more than 16 connections. This does not count direct (single node) entry/exit connections, as these aren't actually controlled by the junction box, nor does it count restricted indirect connections. Note that in some cases the limit on allowed indirect connections may be lower than 16, due to unexplained factors.
While some JBs won't save with more than 11 or 12 indirect connections, we can demonstrate that increasing allowed direct connections does not influence whether the JB will save, and restricting indirect connections does influence whether the JB will save.
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Post by Inactive user -1697532064-
subs5 wrote:How do you know the single node direct path routes aren’t counted? They had before in testing. So I would be wary of including that in wazeopedia w/o Staff confirmation.
Here are a few more recent testing examples. Have staff said that direct connections count? They may have in JB 1.0...
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Last edited by Inactive user -1697532064- on Mon Aug 13, 2018 1:50 pm, edited 1 time in total.
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Post by Inactive user -1697532064-
subs5 wrote:On complex items like this, TollFree/Tolls, and HOV, I have been told that lack of data for ficticious segments have an affect on the algorithm. Real segments that don't get lots of traffic can also affect it. So I am reluctant to be so declarative on a statement. There have been three unannounced changes in a month to JBs so everything is written in Jello.
I understand how that works with routing, but we're not talking about routing. We're talking about what can be saved in WME. If a JB won't save due to too many connections, and restricting direct connections doesn't help, we need to document this. If restricting indirect connections does help, we need to document that (see how I changed "controllable" to "allowed"). I know that JB changes a fair amount, but we try to keep the wiki up to date, right?

And anyway, here's another example in a higher-traffic area. If you allow another JB route from this segment, you can't save the JB, and restricting the right turn into the segment from Crain Hwy doesn't help, so direct connections are not counted for this.
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Post by FzNk
We need to keep the idea of a linear N-S/E-W limit. The area isn't a limiting factor beyond it being a combination of the two real limiting factors and could lead someone to expect to be able to, for example, create a 2000m x 500m JB because its area is less than 1110m x 1110m. I would recommend saying that the maximum N-S height is 0.01 lat. (always 1110m) and the maximum E-W width is [explanation of lon. line distance].
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Post by herrchin
My synthetic tests were performed because I was getting problematic results on a real, busy intersection in production. I could have >16 "direct" connections no problem, but only ~10-12 multi-node indirect connections. So I went for exaggerated examples to try and find consistent limits.
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Post by ojlaw
Errors when editing- Max size

I propose changing the Max size to better reflect the limits. Currently this-

Max size - The size of a junction box cannot exceed 1 kilometer. This is a linear 1 km limit north-south or east-west. If you draw an imaginary 3280 ft x 3280 ft (1 km²) box around the junction box, if the junction box pokes out at any point, then it's too big.

is kind of correct, but not really.

I propose something along the lines of-
Max size - The size of a junction box cannot exceed 0.01°². At the equator this translates to approximately 1110m x 1110m. As you go north or south in latitude the length of a degree decreases on its longitudinal axis while the length remains consistent along the latitudinal axis. In the southernmost part of the continental US 0.01° longitude translates to about 1010m and along the Canadian border(49° N) 0.01° longitude is about 730m. So the max size of a JB in Key West is about 1110m x 1010m(NS x EW) and along the Canadian border the max size is 1110m x 730m(NS x EW).

Also remove the Mbox. Wordsmithing isn't really my thing so I'm open to any suggestions.

The internet offers handy tools to easily check the distance of a degree at certain latitudes, like this
https://www.johndcook.com/how_big_is_a_degree.html

Thanks for the consideration and any feedback.
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Post by ojlaw
good point. i agree that opening with an area statement could be misleading.

how about-
Max size - The length of a junction box cannot exceed 0.01° latitude and 0.01° longitude. The north-south linear limit is always 1110m(0.01°) and the maximum east-west linear limit is variable. As you go north or south in latitude the length of a degree decreases on its longitudinal axis while the length remains consistent along the latitudinal axis. In the southernmost part of the continental US 0.01° longitude translates to about 1010m and along the Canadian border(49° N) 0.01° longitude is about 730m. So the max size of a JB in Key West is about 1110m x 1010m(NS x EW) and along the Canadian border the max size is 1110m x 730m(NS x EW).
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